For me this is what I see with exporting…ie that the look of export is tied to the scaling factor not what the preview looks like…this is 1 by default. So your export will look at the detail level like a 100% sized display preview version… at any other display preview size the export will not match ie it will have the level of detail shown at 100%…if you however you export with a scale to match…say for me around 25% is about what full screen preview size is …then the jpg and display preview match as they have both been scaled the same amount…So a jpg exported at 0.25 will look way more like the full screen preview than one exported with the scale set to 1…at least in my experimentation…similar discussion going on here… Denoising high-ISO images: a sourdough bread - #96 by priort
Once you start to play with all the resizing and preview combinations there may be other considerations but in direct limited testing this is what I see…